We have a 4'x4' chicken coop that is 4 ' high in the back and 5 feet high in the front. There is a door in the 5 foot front, and a window in the front as well, that is covered in winter, and wire in summer. I want to put a floor in it at the 2 foot high mark, making it into a "2 story" Breeding coop for silkies. I know I would have to put a low window in it for the bottom pen, that I could remeove and leave covered with wire in the summer, but what else would I have to do to keep them well enough ventilated. I am thinking that they would be housing a trio or quad of silkies. Oh yeah on one side of the coop there is a "Cupboard shaped thing that that holds the feed water and nests so they don't take up floor space. what else would I have to do to such a building to make it work as a 2 story breeding pen?